Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau |
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摘 要: | Geological mapping data (1:250000) in the Qinghai-Tibet Plateau and its adjacent regions reveal the sediment sequences, distribution and tectonic evolution of the 92 Tertiary remnant basins. Southern Tibet and the Yecheng area in Xinjiang, located at southern and northwestern margins of the Qinghai-Tibet Plateau, respectively, were parts of the Neo-Tethys remnant sea in the Paleogene. In southern Tibet, both the subabyssal and abyssal sequences occur at the Gyangze, Saga, Guoyala, and Sangmai areas. The deep-water facies successions outcrop in the west, whereas the shallow-water facies sequences in the east, indicating the east to the west retreat of the Neo-Tethys Ocean. The retreat of the Neo-Tethys Ocean in the east was contributed to the earlier tectonic uplift of the eastern Qinghai-Tibet Plateau. The uplift process of the Plateau from the Late Cretaceous to Pliocene is described as follows: During the Late Cretaceous, tectonic uplift of the Qinghai-Tibet Plateau occurred in the northeastern part and the configuration of the Qinghai-Tibet Plateau was characterized by rise in the northeast and depression in the west. In the Paleocene-Eocene interval, the Tengchong-Baingoin and Kuyake-Golmud areas experienced local tectonic uplifting, the West Kunlun uplift zone broadened easterly, the Qilian uplift zone broadened southerly, and the Songpan-Garzê uplift zone shrank easterly. The Oligocene configuration of the Qinghai-Tibet Plateau was characterized by mountain chains rising along its margins and sedimentary basins in the central part because of tectonic uplifts of the Gangdisê and the Himalaya blocks. Meanwhile, the Kunlun-Altyn-Qilian uplift zones have also broadened southerly and northerly. In contrast, the great uplift zones of the Gangdisê, the Himalaya, the Karakorum, and the Kunlun blocks characterize the paleogeographic contours of the Qinghai-Tibet Plateau during the Miocene-Pliocene. Additionally, the thermochronological data on tectonic uplift events in southern Tibet, West Kunlun Mountains, Altyn Tagh, eastern Tibet, and western Sichuan all suggest that the most intense deformation occurred at 13-8 Ma and since 5 Ma, respectively, corresponding to two great uplift periods in Neogene. As a result, turnover of paleogeographic configuration of the Qinghai-Tibet Plateau occurred during the Neogene, experiencing a change from high contours in the east in the pre-Oligocene to high contours in the west at the end-Pliocene. The uplift of the Qinghai-Tibet Plateau during the Cenozoic was episodic, and the uplifts of various blocks within the Plateau were spatially and chronologically different.
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Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau |
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Authors: | KeXin Zhang GuoCan Wang Kai Cao Chao Liu ShuYuan Xiang HanLie Hong XiaoHu Kou YaDong Xu FenNing Chen YanNing Meng and RuiMing Chen |
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Institution: | (1) Key Laboratory of Biogeology and Environmental Geology of Ministry of Education, China University of Geosciences, Wuhan, 430074, China;(2) State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, 430074, China;(3) Faulty of Earth Sciences, China University of Geosciences, Wuhan, 430074, China |
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Abstract: | Geological mapping data (1:250000) in the Qinghai-Tibet Plateau and its adjacent regions reveal the sediment sequences, distribution
and tectonic evolution of the 92 Tertiary remnant basins. Southern Tibet and the Yecheng area in Xinjiang, located at southern
and northwestern margins of the Qinghai-Tibet Plateau, respectively, were parts of the Neo-Tethys remnant sea in the Paleogene.
In southern Tibet, both the subabyssal and abyssal sequences occur at the Gyangze, Saga, Guoyala, and Sangmai areas. The deep-water
facies successions outcrop in the west, whereas the shallow-water facies sequences in the east, indicating the east to the
west retreat of the Neo-Tethys Ocean. The retreat of the Neo-Tethys Ocean in the east was contributed to the earlier tectonic
uplift of the eastern Qinghai-Tibet Plateau. The uplift process of the Plateau from the Late Cretaceous to Pliocene is described
as follows: During the Late Cretaceous, tectonic uplift of the Qinghai-Tibet Plateau occurred in the northeastern part and
the configuration of the Qinghai-Tibet Plateau was characterized by rise in the northeast and depression in the west. In the
Paleocene-Eocene interval, the Tengchong-Baingoin and Kuyake-Golmud areas experienced local tectonic uplifting, the West Kunlun
uplift zone broadened easterly, the Qilian uplift zone broadened southerly, and the Songpan-Garzê uplift zone shrank easterly.
The Oligocene configuration of the Qinghai-Tibet Plateau was characterized by mountain chains rising along its margins and
sedimentary basins in the central part because of tectonic uplifts of the Gangdisê and the Himalaya blocks. Meanwhile, the
Kunlun-Altyn-Qilian uplift zones have also broadened southerly and northerly. In contrast, the great uplift zones of the Gangdisê,
the Himalaya, the Karakorum, and the Kunlun blocks characterize the paleogeographic contours of the Qinghai-Tibet Plateau
during the Miocene-Pliocene. Additionally, the thermochronological data on tectonic uplift events in southern Tibet, West
Kunlun Mountains, Altyn Tagh, eastern Tibet, and western Sichuan all suggest that the most intense deformation occurred at
13-8 Ma and since 5 Ma, respectively, corresponding to two great uplift periods in Neogene. As a result, turnover of paleogeographic
configuration of the Qinghai-Tibet Plateau occurred during the Neogene, experiencing a change from high contours in the east
in the pre-Oligocene to high contours in the west at the end-Pliocene. The uplift of the Qinghai-Tibet Plateau during the
Cenozoic was episodic, and the uplifts of various blocks within the Plateau were spatially and chronologically different.
Supported by the National Natural Science Foundation of China (Grant No. 40621002), the Foundation of Geological Survey of
China (Grant No. 1212010610103), and MOE Innovative Research Team Program (Grant No. IRT0546) |
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Keywords: | Cenozoic tectonic uplift thermochronology sedimentary records the Qinghai-Tibet Plateau |
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